#include <stdio.h>
#include <stdlib.h>
typedef int BTNodeType;

typedef struct BinaryTreeNode
{
    BTNodeType _data;
    struct BinaryTreeNode* _left;
    struct BinaryTreeNode* _right;
}BTNode;


//新建节点
BTNode* BuyNode(BTNodeType n);
//前序遍历
void PrevOrder(BTNode* root);

//中序遍历
void InOrder(BTNode* root);

//后序遍历
void PostOrder(BTNode* root);

//求结点个数
size_t NodeSize(BTNode* root);

//求叶子结点个数
size_t LeafNodeSize(BTNode* root);

//求高度
size_t Height(BTNode* root);

//求第k层结点的个数
size_t KSize(BTNode* root,int k);


//查找值为k的结点
BTNode* FindK(BTNode* root,int k);